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<H2>phpBB Coding Standard Guidelines</H2>Comments or suggestions? email <A 
href="mailto:nate@phpbb.com">nate@phpbb.com</A><BR><BR><A 
href="#editor">Editor 
Settings</A><BR><A 
href="#naming">Naming 
Conventions</A><BR><A 
href="#layout">Code Layout</A><BR><A 
href="#general">General 
Guidelines</A><BR><BR><BR><A name=editor></A><A 
href="#top">top</A> 
<H3>Editor Settings</H3>
<P><B>Tabs vs Spaces:</B> In order to make this as simple as possible, we will 
be using tabs, not spaces. Feel free to set how many spaces your editor uses 
when it <B>displays</B> tabs, but make sure that when you <B>save</B> the file, 
it's saving tabs and not spaces. This way, we can each have the code be 
displayed the way we like it, without breaking the layout of the actual files. 
</P>
<P><B>Linefeeds:</B> Ensure that your editor is saving files in the UNIX format. 
This means lines are terminated with a newline, not with a CR/LF combo as they 
are on Win32, or whatever the Mac uses. Any decent Win32 editor should be able 
to do this, but it might not always be the default. Know your editor. If you 
want advice on Windows text editors, just ask one of the developers. Some of 
them do their editing on Win32. </P><BR><BR><A name=naming></A><A 
href="#top">top</A> 
<H3>Naming Conventions</H3>
<P>We will not be using any form of hungarian notation in our naming 
conventions. Many of us believe that hungarian naming is one of the primary code 
obfuscation techniques currently in use. </P>
<P><B>Variable Names:</B> Variable names should be in all lowercase, with words 
separated by an underscore. <BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;Example: <CODE><FONT 
size=+1>$current_user</FONT></CODE> is right, but <CODE><FONT 
size=+1>$currentuser</FONT></CODE> and <CODE><FONT 
size=+1>$currentUser</FONT></CODE> are not. <BR><BR>Names should be descriptive, 
but concise. We don't want huge sentences as our variable names, but typing an 
extra couple of characters is always better than wondering what exactly a 
certain variable is for. </P>
<P><B>Loop Indices:</B> The <I>only</I> situation where a one-character variable 
name is allowed is when it's the index for some looping construct. In this case, 
the index of the outer loop should always be $i. If there's a loop inside that 
loop, its index should be $j, followed by $k, and so on. If the loop is being 
indexed by some already-existing variable with a meaningful name, this guideline 
does not apply. <BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;Example: <PRE><FONT size=+1>
		for ($i = 0; $i &lt; $outer_size; $i++) 
		{
		   for ($j = 0; $j &lt; $inner_size; $j++) 
		   {
		      foo($i, $j);
		   }
		} </FONT></PRE>
<P></P>
<P><B>Function Names:</B> Functions should also be named descriptively. We're 
not programming in C here, we don't want to write functions called things like 
"stristr()". Again, all lower-case names with words separated by a single 
underscore character. Function names should preferably have a verb in them 
somewhere. Good function names are <CODE><FONT 
size=+1>print_login_status()</FONT></CODE>, <CODE><FONT 
size=+1>get_user_data()</FONT></CODE>, etc.. </P>
<P><B>Function Arguments:</B> Arguments are subject to the same guidelines as 
variable names. We don't want a bunch of functions like: <CODE><FONT 
size=+1>do_stuff($a, $b, $c)</FONT></CODE>. In most cases, we'd like to be able 
to tell how to use a function by just looking at its declaration. </P>
<P><B>Summary:</B> The basic philosophy here is to not hurt code clarity for the 
sake of laziness. This has to be balanced by a little bit of common sense, 
though; <CODE><FONT size=+1>print_login_status_for_a_given_user()</FONT></CODE> 
goes too far, for example -- that function would be better named <CODE><FONT 
size=+1>print_user_login_status()</FONT></CODE> , or just <CODE><FONT 
size=+1>print_login_status()</FONT></CODE>. </P><BR><BR><A name=layout></A><A 
href="#top">top</A> 
<H3>Code Layout</H3>
<P><B>Standard header for new files:</B> Here a template of the header that must 
be included at the start of all phpBB files: <PRE><FONT size=+1>
		/***************************************************************************
		                                filename.php
		                             -------------------
		    begin                : Sat June 17 2000
		    copyright            : (C) 2000 The phpBB Group
		    email                : support@phpBB.com
		
		    $Id: codingstandards.htm,v 1.2 2005/07/25 20:02:22 squareing Exp $
		
		 ***************************************************************************/
		
		/***************************************************************************
		 *                                         				                                
		 *   This program is free software; you can redistribute it and/or modify  	
		 *   it under the terms of the GNU General Public License as published by  
		 *   the Free Software Foundation; either version 2 of the License, or	    	
		 *   (at your option) any later version.
		 *
		 ***************************************************************************/
	</FONT></PRE>
<P></P>
<P><B>Always include the braces:</B> This is another case of being too lazy to 
type 2 extra characters causing problems with code clarity. Even if the body of 
some construct is only one line long, do <I>not</I> drop the braces. Just don't. 
<BR><BR>&nbsp;&nbsp;&nbsp;Examples:<PRE><FONT size=+1>
		/* These are all wrong. */
		if (condition)	do_stuff();
		if (condition)
			do_stuff();
		while (condition) 
			do_stuff();
		for ($i = 0; $i &lt; size; $i++)
			do_stuff($i);
		
		/* These are right. */
		if (condition) 
		{
			do_stuff();
		}
		while (condition) 
		{
			do_stuff();
		}
		for ($i = 0; $i &lt; size; $i++) 
		{
			do_stuff();
		}
	</FONT></PRE>
<P></P>
<P><B>Where to put the braces:</B> This one is a bit of a holy war, but we're 
going to use a style that can be summed up in one sentence: Braces always go on 
their own line. The closing brace should also always be at the same column as 
the corresponding opening brace. <BR><BR>&nbsp;&nbsp;&nbsp;Examples:<PRE><FONT size=+1>
		if (condition) 
		{
			while (condition2)
			{
				...
			}
		}
		else 
		{
			...
		}

		for ($i = 0; $i &lt; $size; $i++) 
		{
			...
		}
		
		while (condition) 
		{
			...
		}
		
		function do_stuff() 
		{
			...
		}
	</FONT></PRE>
<P></P>
<P><B>Use spaces between tokens:</B> This is another simple, easy step that 
helps keep code readable without much effort. Whenever you write an assignment, 
expression, etc.. Always leave <I>one</I> space between the tokens. Basically, 
write code as if it was English. Put spaces between variable names and 
operators. Don't put spaces just after an opening bracket or before a closing 
bracket. Don't put spaces just before a comma or a semicolon. This is best shown 
with a few examples. <BR><BR>&nbsp;&nbsp;&nbsp;Examples:<PRE><FONT size=+1>
		/* Each pair shows the wrong way followed by the right way. */
		
		$i=0;
		$i = 0;
		
		if($i&lt;7) ...
		if ($i &lt; 7) ...
		
		if ( ($i &lt; 7)&amp;&amp;($j &gt; 8) ) ...
		if (($i &lt; 7) &amp;&amp; ($j &gt; 8)) ...
		
		do_stuff( $i, "foo", $b );
		do_stuff($i, "foo", $b);
		
		for($i=0; $i&lt;$size; $i++) ...
		for($i = 0; $i &lt; $size; $i++) ... 
		
		$i=($j &lt; $size)?0:1;
		$i = ($j &lt; $size) ? 0 : 1;
	</FONT></PRE>
<P></P>
<P><B>Operator precedence:</B> Do you know the exact precedence of all the 
operators in PHP? Neither do I. Don't guess. Always make it obvious by using 
brackets to force the precedence of an equation so you know what it does. 
<BR><BR>&nbsp;&nbsp;&nbsp;Examples:<PRE><FONT size=+1>
		/* what's the result? who knows. */
		$bool = ($i &lt; 7 &amp;&amp; $j &gt; 8 || $k == 4);
		
		/* now you can be certain what I'm doing here. */
		$bool = (($i &lt; 7) &amp;&amp; (($j &lt; 8) || ($k == 4)))
		</FONT></PRE>
<P></P>
<P><B>SQL code layout:</B> Since we'll all be using different editor settings, 
don't try to do anything complex like aligning columns in SQL code. Do, however, 
break statements onto their own lines. Here's a sample of how SQL code should 
look. Note where the lines break, the capitalization, and the use of brackets. 
<BR><BR>&nbsp;&nbsp;&nbsp;Examples:<PRE><FONT size=+1>
		SELECT field1 AS something, field2, field3
		FROM table a, table b
		WHERE (this = that) AND (this2 = that2)
		</FONT></PRE>
<P></P>
<P><B>SQL insert statements:</B> SQL INSERT statements can be written in two 
different ways. Either you specify explicitly the columns being inserted, or
you rely on knowing the order of the columns in the database and do not
specify them. We want to use the former approach, where it is explicitly
stated whcih columns are being inserted. This means our application-level code
will not depend on the order of the fields in the database, and will not be broken
if we add additional fields (unless they're specified as NOT NULL, of course).
<BR><BR>&nbsp;&nbsp;&nbsp;Examples:<PRE><FONT size=+1>
		# This is not what we want.
		INSERT INTO mytable
		VALUES ('something', 1, 'else')
		
		# This is correct.
		INSERT INTO mytable (column1, column2, column3)
		VALUES ('something', 1, 'else')
		</FONT></PRE>		
<P></P><BR><BR><A name=general></A><A 
href="#top">top</A> 
<H3>General Guidelines</H3>
<P><B>Quoting strings:</B> There are two different ways to quote strings in PHP 
- either with single quotes or with double quotes. The main difference is that 
the parser does variable interpolation in double-quoted strings, but not in 
single quoted strings. Because of this, you should <I>always</I> use single 
quotes <I>unless</I> you specifically need variable interpolation to be done on 
that string. This way, we can save the parser the trouble of parsing a bunch of 
strings where no interpolation needs to be done. Also, if you are using a string 
variable as part of a function call, you do not need to enclose that variable in 
quotes. Again, this will just make unnecessary work for the parser. Note, 
however, that nearly all of the escape sequences that exist for double-quoted 
strings will not work with single-quoted strings. Be careful, and feel free to 
break this guideline if it's making your code harder to read. 
<BR><BR>&nbsp;&nbsp;&nbsp;Examples:<PRE><FONT size=+1>
		/* wrong */
		$str = "This is a really long string with no variables for the parser to find.";
		do_stuff("$str");
		
		/* right */
		$str = 'This is a really long string with no variables for the parser to find.';
		do_stuff($str);
		</FONT></PRE>
<P></P>
<P><B>Associative array keys:</B> In PHP, it's legal to use a literal string as 
a key to an associative array without quoting that string. We don't want to do 
this -- the string should always be quoted to avoid confusion. Note that this is 
only when we're using a literal, not when we're using a variable. 
<BR><BR>&nbsp;&nbsp;&nbsp;Examples:<PRE><FONT size=+1>
		/* wrong */
		$foo = $assoc_array[blah];
		
		/* right */
		$foo = $assoc_array['blah'];
		</FONT></PRE>
<P></P>
<P><B>Comments:</B> Each function should be preceded by a comment that tells a 
programmer everything they need to know to use that function. The meaning of 
every parameter, the expected input, and the output are required as a minimal 
comment. The function's behaviour in error conditions (and what those error 
conditions are) should also be present. Nobody should have to look at the actual 
source of a function in order to be able to call it with confidence in their own 
code. <BR><BR>In addition, commenting any tricky, obscure, or otherwise 
not-immediately-obvious code is clearly something we should be doing. Especially 
important to document are any assumptions your code makes, or preconditions for 
its proper operation. Any one of the developers should be able to look at any 
part of the application and figure out what's going on in a reasonable amount of 
time. </P>
<P><B>Magic numbers:</B> Don't use them. Use named constants for any literal 
value other than obvious special cases. Basically, it's OK to check if an array 
has 0 elements by using the literal 0. It's not OK to assign some special 
meaning to a number and then use it everywhere as a literal. This hurts 
readability AND maintainability. Included in this guideline is that we should be 
using the constants TRUE and FALSE in place of the literals 1 and 0 -- even 
though they have the same values, it's more obvious what the actual logic is 
when you use the named constants. </P>
<P><B>Shortcut operators:</B> The only shortcut operators that cause readability 
problems are the shortcut increment ($i++) and decrement ($j--) operators. These 
operators should not be used as part of an expression. They can, however, be 
used on their own line. Using them in expressions is just not worth the 
headaches when debugging. <BR><BR>&nbsp;&nbsp;&nbsp;Examples:<PRE><FONT size=+1>
		/* wrong */
		$array[++$i] = $j;
		$array[$i++] = $k;
		
		
		/* right */
		$i++;
		$array[$i] = $j;
		
		$array[$i] = $k;
		$i++;
		</FONT></PRE>
<P></P>
<P><B>Inline conditionals:</B> Inline conditionals should only be used to do 
very simple things. Preferably, they will only be used to do assignments, and 
not for function calls or anything complex at all. They can be harmful to 
readability if used incorrectly, so don't fall in love with saving typing by 
using them. <BR><BR>&nbsp;&nbsp;&nbsp;Examples:<PRE><FONT size=+1>
		/* Bad place to use them */
		(($i &lt; $size) &amp;&amp; ($j &gt; $size)) ? do_stuff($foo) : do_stuff($bar);
		
		
		/* OK place to use them */
		$min = ($i &lt; $j) ? $i : $j;
		</FONT></PRE>
<P></P>
<P><B>Don't use uninitialized variables.</B> for phpBB 2, we intend to use a 
higher level of run-time error reporting. This will mean that the use of an 
uninitialized variable will be reported as an error. This will come up most 
often when checking which HTML form variables were passed. These errors can be 
avoided by using the built-in isset() function to check whether a variable has 
been set. <BR><BR>&nbsp;&nbsp;&nbsp;Examples:<PRE><FONT size=+1>
		/* Old way */
		if ($forum) ...
		
		
		/* New way */
		if (isset($forum)) ...
		</FONT></PRE>
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